A new species of Tychus Leach, 1817 from Lebanon (Coleoptera, Staphylinidae, Pselaphinae).

Tychus meggiolaroi sp. n. from Lebanon is described and illustrated.

A new species of Pselaphogenius Reitter, 1910 of the fiorii species group from southern Italy (Coleoptera, Staphylinidae, Pselaphinae).

Pselaphogenius chloe sp. n. belonging to the fiorii species group is described.

A review of the Tychobythinus algiricus species group from North Africa (Coleoptera: Staphylinidae: Pselaphinae).

The species belonging to the Tychobythinus algiricus group are revised and the group is characterized and defined. Tychobythinus algiricus (Raffray, 1871) is redescribed, illustrated and its distribution and its synonymic framework discussed, establishing that Tychobythinus occidentalis Besuchet, 1962 is a junior synonym of Tychobythinus algiricus (syn. nov.

The problem of the origin of primordial germ cells (PGCs) in vertebrates: historical review and a possible solution.

A concise review of the articles about the origin of primordial germ cells (PGCs) in vertebrates is provided. Differences among various taxa concerning the origin of PGCs, not easily understandable on the base of traditional knowledge, are pointed out. All those differences can be explained taking into consideration the recent “theory of the endoderm as secondary layer”.